1. Technical Field
The present invention relates generally to an ultra-wideband tapered slot antenna and, more particularly, to an ultra-wideband tapered slot antenna in which C-shaped stubs and a spiral slot are formed in the feed line of the antenna, thus implementing band-stop characteristics in dual bands (e.g., 3.5/5.5 GHz bands).
2. Description of the Related Art
Thanks to the advantages of low power, low cost, and high-speed data transmission, it is expected that ultra-wideband (UWB) systems will be widely applied to the fields of a next-generation Wireless Personal Area Network (WPAN), such as a wireless home network, and a short-range radar system.
However, a frequency band allocated to UWB systems is a 3.1 to 10.6 GHz band, and overlaps the World interoperability for Microwave Access (WiMAX) frequency band for IEEE 802.16 which is operated in a 3.3 to 3.7 GHz band and a Wireless Local Area Network (WLAN) frequency band for IEEE 802.11a which is operated in a 5.15 to 5.825 GHz band. Therefore, in order to solve the problem of electromagnetic interference (EMI) between the UWB system, a 3.5 GHz WiMAX system, and a 5.5 GHz WLAN system, a UWB antenna having a dual-band stop (rejection) function is required.
As antennas for UWB systems, a tapered slot antenna, a bow-tie antenna, a discone antenna, a monopole antenna, etc. are known. In particular, a Tapered Slot Antenna (TSA), which is a directional antenna, has been widely applied to the field of short-range radar systems. Related preceding technologies such as U.S. Pat. Nos. 4,843,403, 5,081,466, and 5,519,408 disclose various types of ultra-wideband tapered slot antennas. However, these conventional antennas are problematic in that they do not have a band-stop function.
As other preceding technologies, Korean Patent No. 10-1116851 and Korean Patent Application Publication No. 10-2007-0058852 disclose an ultra-wideband antenna having a band-stop function. In the above patents, ultra-wideband monopole antennas in which various slots such as U- or V-shaped slots are formed in a radiating element and which are capable of rejecting an undesired frequency band have been widely proposed. However, conventional UWB monopole antennas having a band-stop function are disadvantageous in that, since slots are arranged in a radiating element, the distortion of a radiation pattern in a stop band is caused.